/**
 * @file     search.cpp
 * @brief
 * @author   DuYong
 * @date     2021-03-12
 */
class Solution {
public:
    int search(vector<int>& nums, int target) {
        int left = 0;
        int right = nums.size() - 1;

        while(left <= right) {
            int mid = left + (right - left) / 2;
            if(nums[mid] == target) {
                return mid;
            }
            else if(nums[left] <= nums[mid]) { // the bottom half is sorted
                if(target >= nums[left] && target < nums[mid]) {
                    right = mid - 1;
                }
                else {
                    left = mid + 1;
                }
            }
            else { // the upper half is sorted
                if(target > nums[mid]  && target <= nums[right]) {
                    left = mid + 1;
                }
                else {
                    right = mid - 1;
                }
            }
        }

        return -1;
    }
};